1. Technical Field
The present invention relates to a motor position and velocity detecting system, and more particularly, to a motor position and velocity detecting system capable of accurately detecting a position and a velocity of a motor without adding a hall sensor or the number of poles of the motor.
2. Description of the Related Art
Generally, a motor generates rotation force by attaching a magnet to a rotor having at least two polarities and includes a stator having a coil wound therearound and the rotor rotatably installed in the stator, wherein the center of the rotor is provided with a shaft for outputting the rotation force of the rotor to the outside.
The shaft has a plurality of magnets attached to an outer side thereof, wherein the magnets may be uniformly divided and magnetized by a desired number. The magnet may include a hall sensor installed in the vicinity of an outer peripheral surface thereof and measuring a velocity of the motor, wherein the hall sensor has, an output waveform input to a control arithmetic apparatus to allow the velocity of the motor to be measured.
The hall sensor uses a Hall effect that a potential difference is generated in a direction vertical to those of both of current and a magnetic field when the current flows in a conductor or a semiconductor and the magnetic field are applied in a direction vertical to that of the current to generate Hall voltage that is in proportion to the product between the magnetic field and the control current in the direction vertical to those of both of the current and the magnetic field by allowing the current to flow between input terminals and applying the magnetic field to a sensor surface in the direction vertical to that of the current.
This motor includes the magnet attached to the rotor thereof and having at least two poles in order to obtain a magnetic field from a rotating magnetic field of the stator, rotates to change a polarity of the magnet from an N pole into an S pole or from the S pole into the N pole, and obtains an output waveform through the hall sensor installed at an outer side thereof. This output waveform is input to the control arithmetic apparatus and the control arithmetic apparatus senses an adjacent edge to calculate a pulse width and then calculates a current velocity of the motor. Therefore, the velocity and the position of the motor need to be accurately detected.
According to the related art, in order to increase accuracy in detecting the velocity of the motor, the hall sensor or the number of poles of the motor has been added. However, in this method, a manufacturing process of the motor should be changed and an additional cost should be required.